Crisis inspires innovation! We developed Crafty Microbiology to teach essential microbiology skills at home using safe, common, cheap craft supplies and disposable lab tools.
A.M. Estes, A.S. Jozwick, and J.E. Kerr 2021
How can you teach students fundamental microbiology skills at home – safely? The COVID-19 pandemic has been quite the disruptor for educators and students alike. To stop the spread of this virus, we human hosts need to stay away from each other! SARS-CoV2 is super tricky since many infected people don’t show symptoms or have mild symptoms. So what do you do when the skills your students need to learn can’t be done face-to-face?
In-person Microbiology Labs
Microbiology laboratory, in particular, is tough to teach to students at home. Typically students learn how to grow and test non-disease-causing bacteria in the Microbiology teaching labs on campus. Growing bacteria requires special media “food” for the bacteria, incubators to keep the cultures at the right temperature, and lab equipment – including Bunsen burners and special tools for moving the bacteria.
A fundamental skill is learning “Sterile” or “Aseptic” technique. Students learn how to grow only the non-pathogenic, Risk Group 1 microbes they are given. Sounds easy – right? Well, no. Bacteria are invisible and everywhere. People are walking bags of microbes (humbling – eh?). We constantly shed bacteria and other microbes from our skin, mouth, nose, and clothes. While most of our microbes are harmless, some aren’t. The environment of a building also has microbes in it – in the air, surfaces, pencils, etc… Microbes are everywhere. We don’t want students accidently growing pathogens. Learning proper aseptic technique is essential, but can be tough!
To keep students safe, instructor guidance is essential, but so is the room set-up and resources. We have a BioSafety officer who checks the labs routinely. The American Society for Microbiology has a series of biosafety rules for protecting students on campus. Safety is essential. We can’t monitor and control the safety of a home environment. Additionally home situations are diverse and may include immunocompromised individuals, kids, and pets. Due to all this, the American Society for Microbiology discourages the use of living organisms in student homes.
For more information on the microbial Risk Group classification and proper biosafety see this neat CDC BioSafety click-and-learn.
Virtual Labs Have Issues
What’s an instructor to do? Some turn to virtual, video-game-like training. But many of these virtual labs cost lots of money for either the student, the school, or both. There are some free ones – HHMI Biointeractive, Virtual Microscope – but many, like Virtual Lab, are Flash-based, which is now inactive. Additionally, virtual training might get the ideas across, but students cannot develop the hands-on skills that they really need and want. Theory is important, but its in the actual doing the work that muscle memory is formed and student understanding really takes hold.
“Crafty Microbiology” To The Rescue
Our solution? Crafty Microbiology! Craft supplies partnered with disposable lab tools to teach fundamental lab skills safely at home! Two other microbiology professors, Dr. Jennifer Kerr, Notre Dame of Maryland University, Dr. Anna Jozwick, Goucher College, and I spent our summer months in 2020 creating or improving existing exercises (Herzog and Mawn, 2020; Axler-DiPerte GL. 2017; Hartmann 2011). I had developed a glitter and paint Serial Dilution exercise for my oldest daughter’s 3rd grade STEM night back in 2016. Posting some trial examples to Twitter was encouraging. So several Zoom sessions, brainstorming, and lots of glitter later – we three “Microbiome Mamas” developed a total of 9 exercises to teach the basic ASM microbiology laboratory skills: Aseptic technique, proper personal protective equipment (PPE) removal, microscopy and stains, streaking for single isolates, plating a lawn, serial dilution, antibiotic resistance assays, inoculating media, modeling disease spread, and filtering microbes.
The student’s guide was released as an educational preprint in September so other instructors could use it during Fall 2020 semester while the paper was under peer review for the Journal of Microbiology and Biology Education’s Teaching in a Time of Crisis edition. In each Crafty Microbiology exercise, we explain why that technique is used in microbiology, provide videos to people doing the technique with live microbes, and explain why we use the particular craft supplies that we use.
The Importance of Student Buy-In
Unconventional teaching techniques like Crafty Microbiology need transparency and student buy-in in order to even get a chance. I knew giving students a bag filled with craft supplies was dicey. Even with lab tools, yogurt starters, and a MudWatt – students would probably be wary. So the student and instructor handouts for Crafty Microbiology needed to reflect the thought that we had put into teaching these skills safely.
WHY did we give them the glitter size and density we did? WHY are we using aluminum foil, waxed paper, and then parafilm to learn proper streaking techniques? WHY does it matter that for the antibiotic resistance assay the ink in the magic markers needs to be able to dissolve in water and the mock ‘antibiotics’ need to include water-based, oil, and alcohol-based solutions? Without explaining the reasons behind what we were asking them to do, we’d surely get ignored, scorned, or at least a lot of eye-rolls.
Proper Streaking is Essential
Students struggle to master “streaking for single isolates”, an essential skill. To study what each individual species or strain of microbe can do, first you need to get it growing by itself. Since there can be millions to billions of microbial cells in a drop of water or bit of soil, separating out individual microbial cells is essential. Only then with a pure culture can you start doing tests. However, streaking for single isolates can be challenging. You’re working with clear fluid that you can’t really see to move microscopic organisms around on a dish of microbe-food. Then you put the food with the microbes in a warm incubator and come back 12- 24 hours later. If you’ve messed up and the microbes are not separated, you repeat this, wait, look, repeat or move forward. It can get really frustrating and students are stuck at “streaking” for weeks.
Streaking the “Crafty Micro” Way
To teach Crafty Micro streaking using glitter and disposable lab loops, we broke the technique down into steps. Students learn how to 1) hold and move the loop on the paper and the pattern used to separate the microbial cells, 2) streak in a sterile manner by “flaming” your loop (students get a tube with a picture of a bunsen burner on it and water in it for “killing” the microbes), 3) streak gently so the media isn’t gouged, and 4) practice moving the glitter “microbes” on a gelatin plate that is similar to real media. Yup, we’re having student streak glitter onto a plate of Jello.
In working through the streaking exercise with the students during synchronous labs via Zoom, it worked! Students enjoyed the challenge, understood why we were breaking the steps down and produced good results! Honestly, when we do go back to in-person labs (maybe Spring 2022 in the U.S?!), I’m still going to have students learn this way. I bet they’ll be less frustrated and more successful with the live microbes, but we’ll see. COVID-19 is still a problem here in the U.S., so I can’t bring in the students who learned this way to see if they are more or less successful.
Understanding the Kirby-Bauer method for determining antibiotic resistance is another essential Microbiology skill. After all, antibiotic resistance is a global health-care crisis. In a “live microbe” lab class, students would spread bacteria across media, then place paper discs soaked in antibiotics on top of the bacteria. This grows overnight. The solid white background seen in Figure 2A is the living bacteria. The clear places around the white disks are where the antibiotics have stopped bacterial growth. Sometimes when students spread the liquid bacteria on the plate, they don’t turn the plate well or leave gaps across the plate. They then can’t tell is the clear parts on the plate are due to the antibiotic or poor technique. They don’t see this for a few days and have forgotten their streak technique during the meantime.
Kirby-Bauer (K-B) Technique for determining antibiotic resistance of bacteria. A) A standard K-B plate with live microbes (creamy-white background). Clearings around the white antibiotic-soaked disks indicate bacteria can’t grow due to the drug. B) Mock K-B plate in Crafty Micro. The blue water-soluble magic marker represents the live bacteria. Oil, diltued soap, hand sanitizer, water, etc.. are added to mimic antibiotics. C) Students measure the clearance zone to assess ‘sensitivity’. Photo A by Kylie Brandt, B and C by Anne M. Estes
Photos B and C are of the Crafty Micro method. Here students use a washable magic marker to ‘spread the bacteria’ across the plate. Using a magic marker, instead of a clear liquid with microscopic bacteria, helps students understand how they need to turn the plate to cover the media completely. Using several mock ‘antibiotic agents’ (oil, hand sanitizer, dish soap at full strength and diluted, and water) with different solubility in water gives students a variety of ‘zones of inhibition’ to measure. When students do 3 replicates of this experiment they have quantitative data to analyze and compare across the class! It was exciting to see this really work well across my 50 students in the Fall 2020 semester. I would demo the technique and then they would do it. We all shared results on Zoom!
Does “Crafty Microbiology” Work?
So do students learn microbiology skills using glitter and such? Good question – we don’t know (I feel like I say that a lot as a scientist and teacher). However, in this case, we can work towards answering the question of effectiveness. Dr. Jozwick and Dr. Kerr and I are now embarking on a formal study to see if Crafty Micro is a valid way to teach these essential microbiology skills. We’d love it if you’d join us!
If you are an educator and would like to test these techniques in your classroom, please click on this hyperlink to sign up for the study. If you would like a copy of the entire Crafty Microbiology Instructor and Student Guide with recipes and product numbers, follow this link to the published manuscript. If you’d like to be added to a mailing list as changes are made to Crafty Microbiology, please sign up below.
Please email any of us with questions or concerns. If you are an ASM member, we have a thread on ASM microEdu Slack for questions and concerns.
Finally, Crafty Microbiology was created to be modular and for instructors (K-12 and university) to tailor to fit their own classes. Use one or two exercises or all of them. We hope Crafty Micro helps during this crazy world of COVID-inspired virtual learning, but also want this used for outreach in the future. Anna, Jenn, and I all do a lot of outreach. Heck, I met Anna when we both helped with an ASM outreach event at Morgan State University! Plus, it was an outreach STEM night for Jac’s 3rd grade class years ago, where this all first began.
References and Additional Resources
Axler-DiPerte GL. 2017. Modeling and Visualizing Bacterial Colony Purification Without the Use of Bacteria or Laboratory Equipment. J. Microbiol. Biol. Educ. 18:18.2.41. doi: 10.1128/jmbe.v18i2.1308
CDC 2009. Biosafety in Microbiological and Biomedical Laboratories 5th edition. HHS Publication No. (CDC) 21-1112.
Hartman D. 2011. Perfecting Your Spread Plate Technique. J. Microbiol. Biol. Educ., 12:2, 204–205. doi:10.1128/jmbe.v12i2.324
Horack 2020. Virtual Resources to Teach Microbiology Techniques and Experiments
Kaiser DG .2016. Aseptic Technique: Inoculating a Petri Plate – Streaking for Isolation [Video]. YouTube. Available: https://www.youtube.com/watch?v=oX10mXkg-B8
Mostly Microbes YouTube “Crafty Microbiology” Playlist
A. M. Estes 2015. Modeling the Digestive System Microbiome. J. Microbiol. Biol. Educ. vol. 16 no. 2 271-273. doi:10.1128/jmbe.v16i2.908